Preparation of Binder-Free Spherical Submicron-Sized Platinum Particles Using Laser Melting in Liquids

Abstract

Spherical-shaped submicron-sized particles (SMPs) of noble metals are an ideal material to prepare electronic wires using ink-jet printing. Platinum SMPs (PtSMPs) must be a better material than gold SMPs (AuSMPs) used in high temperature conditions, because of the higher melting point of platinum than that of gold. However, differing from AuSMPs, no convenient PtSMP preparation method have been developed so far. In the present study, we have applied the laser melting in liquids method (LML), which has been used to prepare SMPs of various materials, on the preparation of PtSMPs. The results showed that PtSMPs were successfully obtained by laser irradiation at 266 nm for platinum nanoparticles stabilized by a small amount of sodium citrate via the laser-induced agglomeration. It was also found that PtSMPs of the similar size were obtained when laser wavelength was changed to 355 nm, although the irradiation time necessary to induce NP agglomeration using 355 nm laser irradiation became longer than that using 266 nm laser irradiation. This laser wavelength dependence was explained in terms of the size-dependent heating efficiency of platinum particles.